On Mon, Jan 25, 2016 at 02:27:25PM +0530, Bharata B Rao wrote: > On Sat, Jan 23, 2016 at 11:47:22AM -0200, Eduardo Habkost wrote: > > On Fri, Jan 08, 2016 at 12:25:09PM +0530, Bharata B Rao wrote: > > > Prevent guests from booting with CPU topologies that have partially > > > filled CPU cores or can result in partially filled CPU cores after > > > CPU hotplug like > > > > > > -smp 15,sockets=1,cores=4,threads=4,maxcpus=16 or > > > -smp 15,sockets=1,cores=4,threads=4,maxcpus=17. > > > > > > This is enforced by introducing MachineClass::validate_smp_config() > > > that gets called from generic SMP parsing code. Machine type versions > > > that don't want to enforce this can override this method. > > > > > > TODO: Only sPAPR and PC changes are done in this patch, other archs > > > will be touched after there is agreement on this approach. > > > > > > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com> > > > --- > > > hw/core/machine.c | 20 ++++++++++++++++++++ > > > hw/i386/pc_piix.c | 7 +++++++ > > > hw/i386/pc_q35.c | 7 +++++++ > > > hw/ppc/spapr.c | 7 +++++++ > > > include/hw/boards.h | 1 + > > > vl.c | 4 ++++ > > > 6 files changed, 46 insertions(+) > > > > > > diff --git a/hw/core/machine.c b/hw/core/machine.c > > > index c46ddc7..b66c101 100644 > > > --- a/hw/core/machine.c > > > +++ b/hw/core/machine.c > > > @@ -336,6 +336,25 @@ static void machine_init_notify(Notifier *notifier, > > > void *data) > > > foreach_dynamic_sysbus_device(error_on_sysbus_device, NULL); > > > } > > > > > > +static int validate_smp_config_generic(int smp_cpus, int max_cpus, > > > + int smp_threads) > > > > Please make it use a Error** parameter to return error > > information, and let the caller decide what to do with the error > > message. One day the mc->validate_smp_config() call may be moved > > inside a function that returns error information using Error** > > and needs to propagate it to the caller. > > Sure, will make this change. > > I see that not all target archs use machine type versions and even > if they do it will not be a one-line changer (as shown for i386 and sPAPR in > this patch) for them to override mc->validate_smp_config() for older > versions. > > So am I expected to change .class_init routine for all these archs by > setting mc->validate_smp_config() to a NOP validate_smp_config() > so that the default validate_smp_config() defined for TYPE_MACHINE > is overridden ? In order to preserve the existing behaviour with > CPU topology for all args, it appears that such a change would be > necessary, but I am not sure how to test all of them. Will just a compile > test do ?
I am not sure I understand the question: if you want most machine classes to have a NOP validate_smp_config(), why do you want to make validate_smp_config_generic() the default in TYPE_MACHINE? Just make a more convenient default in TYPE_MACHINE, and override it in the pc and spapr base classes. In other words, if you don't want to risk breaking other machine classes, you just need explicit one-line validate_smp_config assignments in 5 class_init/machine_options functions: Class | validate_smp_config pointer -------------------+------------------------------ TYPE_MACHINE | NULL (no explicit assignment) TYPE_PC_MACHINE | validate_smp_config_generic TYPE_SPAPR_MACHINE | validate_smp_config_generic pc-i440fx-2.5 | NULL pc-q35-2.5 | NULL spapr-2.5 | NULL -- Eduardo
